Whether you lift light weights many times or heavy weights fewer times—both can make you stronger in exercises like squats and deadlifts, as long as you push to exhaustion.

Scientific Claim

Low-load resistance training (20-25 repetitions to volitional failure) and high-load resistance training (3-5 repetitions to volitional failure) are associated with similar increases in maximal strength (21 ± 10%) for multi-joint movements in resistance-trained adults aged 26.4 ± 4.4 years over a 9-week period.

Original Statement

“The training regimens led to comparable increases in 1 RM in multi-joint movements (21 ± 10%)”

From study:Divergent Strength Gains but Similar Hypertrophy After Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome.

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design cannot support claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The abstract does not explicitly state randomization or control group design per GRADE rules; thus, causation cannot be confirmed. Language implies equivalence but only association is supported.

Evidence from Studies

Supporting (1)

Divergent Strength Gains but Similar Hypertrophy After Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome.

Randomized Controlled Trial

Human

2025 Sep 1

This study found that lifting light weights for many reps and lifting heavy weights for few reps both made people just as strong in exercises like squats and deadlifts, as long as they pushed to exhaustion.

Contradicting (0)

No contradicting evidence found

Source Study

Divergent Strength Gains but Similar Hypertrophy After Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome.

Score: 25

DOI: 10.1152/japplphysiol.00353.2025

Similar Assertions

For exercises that move just one joint—like bicep curls—lifting heavier weights leads to better strength gains than lifting lighter weights, even if both are done until exhaustion.

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Doing leg exercises with both legs at the same time for 12 weeks makes you stronger at lifting with both legs together, while doing them one leg at a time makes you stronger at lifting with each leg separately.

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Using light weights until you're exhausted or slow builds your muscle stamina better than heavy weights, but doesn't make you as strong as lifting heavy weights.

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Even though your body releases similar growth hormones after light workouts whether you rest a little or a lot, you still get stronger and bigger muscles either way.

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You can get stronger and bigger muscles by lifting light weights until you're exhausted — even if you never lift heavy, which challenges the old idea that heavy weights are required.

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